Interlocked pressure roller and pad roller



Feb. 19, 1952 s BARTELSQN 2,586,600

INTERLOCKED PRESSURE ROLLER AND PAD ROLLER Filed Sept. 7, 1946 INVENTOR.

fie): Eda/k250i: MMWW Patented Feb. 19, 1952 INTERLOCKEDTIRESSURE. ROLLER AND PADf'ROLLER.

Sten Bartelson,z;llshland, N. J., assignor to Radio Corporation'of America, a. corporation of Delaware Application September 7, 1946, Serial N 0. 695,500 4 Claims. (01. 271-23) vanced. Although the invention is shownincorporated with a pressure roller on a sound 'film drum, it is to be understood that it may also-.be applied to "one or more sprockets which are adapted to actually drive the fihnh In Zimmerman-U. S. Patent-No. 2,219,731 of October 29, 1940, there is disclosed and claimed a toggle type of pad roller for a film advancing sprocket, the film being pulled by the sprocket over a drum. In such a drive mechanism, a pressure roller rests firmly against the surface of the film causing it to engage the supporting drum at all'times. This pressure roller is a particularly important element for obtaining constant speed of the film past the light beam regardless of whether the light beam is a modulated recording beam or a constant intensity' reproducing beam. If the driving mechanism is actuated with the pressure roller in the threading position; that is, spaced from the drumto permit threading of the film between the drum and roller, there is slippage between the film and the drum, thus inducing a variable speedto the film at the translation point. Furthermore;' the film will separate from the surface of the roller causing the sound track to be out of. focus. Thus, it is important that the pressure roller be in position at all times that the film is being advanced through the mechanism.

In threading a motion picture projector, pad rollers are used on the sprockets as disclosed in the above-identified patent. The operator, seldom if ever, fails to close the pad rollers, but frequently forgets to place the pressure roller in operative position against the film. To prevent this, the present invention provides means whereby the closing of the pad roller automatically closes the pressure roller. In this manner, whenever the film is threaded in a recorder orreproducer, there is no chance that the pressure roller will not be in its operative position when A still further object of the invention is to provide an interlockin'gpad roller and pressure roller combination whereby the closing of the pad roller automatically closes the pressure roller.

Although the novel features which are believed to be characteristic of this invention will be pointed out with particularity in the appended claims, the manner ofits organization and the mode of its operation will be better understood by referring to the following description read in conjunction with the accompanying drawings, forming a part hereof, in which:

Fig. 1 is a side elevational view of a soundhead showing the pad roller-pressure roller actuating mechanism of the invention in operative position.

Fig. 2 i a side elevational view, similar to Fig. 1, showing the pad and pressure rollers in inoperative or threading. position, and

Fig. 3 is an enlarged detail view of the pressure roller mounting.

Referring now to the drawings, in which the same numerals refer to like elements, the soundhead is constructed in general accordance with Loomis et. a1. U. S. Patent No. 2,019,147 of October 29, 1935, while it utilizes the pad roller invention disclosed in the above-mentioned Zimmerman patent. In a casing II] is a sprocket H and a film drum l2 adapted to support a film l3 and carry it past the optical system I4 which directs a fine line of light thereupon from an exciter lamp I5. This light; after passing through the portion of the film overhanging the drum I2, is directed by a prism arrangement to a photocell housed within the shield H. The sprocket II is driven from an appropriate source of power and pulls the film over the drum l2, which is provided with a viscous damper as disclosed in the above-mentioned Loomis et. al. patent. From the sprocket II, the film is pulled downwardly, passing out of the casing I0 through an aperture l8. Between the sprocket II and drum I2 is a filter arrangement composed of rollers 20 and 2| pivoted on an arm 22 mounted on a spring and dashpot mechanism 24.

The film is held on the sprocket I I by the pad roller construction 26 shown in the above-identifled Zimmerman patent, while the fihn is held on the drum l2 by a pressure roller 21 having a resilient tire 28. (See Fig. 3.) The roller 27 is mounted on an arm 30 pivoted at 3!. Extending rearwardly from the pivot 3| is an arm 33 between which and an abutment 36 on the casing I0 is inserted a coil spring 34. A flexible shaft 88 from the pad roller 25 extends through a conduit 31 and through the coil spring 34 to the arm 26 is closed, the pressure roller 21 is broughtinto contact with the film in operative position.

With this arrangement, therefore, the possibility of not having the pressure roller in closed position on the drum I2 is eliminated when thepad roller 26 is closed. There is thus no opportunity for the driving mechanism to be actuated without the proper arrangement of all driving elements of the advancing mechanism.

I claim:

1. A film drive mechanism comprising a sprocket adapted to advance a film thereover, a drum adapted to have film pulled thereover by said sprocket and positioned at a distance from said sprocket, a pad roller adapted to maintain said film on said sprocket, a sup-port for said pad roller, a pressure roller adapted to press said film against said drum at apredetermined pressure, a support for said pressure roller, a mounting for said support, means interconnecting said pad roller support and a part of said pressure roller support to cause said pressure roller to ward and away from said drum when said pad roller is moved toward and away from said sprocket, respectively, and tensioning means through which said interconnecting means passes, said tensioning means contacting a part of said mounting and said part of said pressure roller support to cause said pressure roller to exert said predetermined pressure on said film.

2. A film advancing mechanism in accord-' ance with claim 1, in which said interconnecting means comprises a flexible shaft connected to said support for said pad roller and said part of said support for said pressure roller, and said tensioning means is a coil spring around said interconnecting means between said part of said mounting and said part of said support for said pressure roller.

3. In a film advancing mechanism, a sprocket for advancing film thereover, a pad roller for holding film on said sprocket, an arm pivoted at one end and having said pad roller mounted on the other end thereof, a drum over which film is pulled by said sprocket, a pressure roller adapted to press said film on the surface of said drum, an arm pivoted at one end and having said pressure roller on the other end thereof, a second arm fixed to said first pressure roller arm, a shaft movable longitudinally and interconnecting theend of said last mentioned arm and said pad roller arm, movement of said pad roller toward said sprocket actuating said pressure roller toward said drum, a casing and tensioning means through which said shaft passes and which is positioned between the end of said last mentioned arm and a part of said casing.

4. A filmadvancing mechanism in accordance with claim 3, in which said shaft is flexible and said tensioning means is a coil spring for exerting a predetermined pressure of said pressure roller on said film when said pad roller is in operative position. v

STEN E. BARTELSON.

REFERENCES CITED 'lhe following references are of record in the file of this patent:

UNITED STATES PATENTS .Number Name Date 975,497 Becker Nov. 15, 1910 1,782,470 Heisler Nov. 25, 1930 1,843,982 Kreider Feb. 9, 1932 I 2,022,492 Clay Nov. 26, 1935 2,341,935 Maus et a1. Feb. 15, 1944 2,418,545 Zimmerman Apr. 8, 1947 FOREIGN PATENTS Number Country Date 337,415 Germany May 31, 1921 

